Quantum Duplex Coding
Fakhar Zaman, Hyundong Shin, Moe Z. Win
Abstract
Counterfactual quantum communication---sending information between two remote parties without transmitting any physical particle over the channel---is unique in quantum protocols. By harnessing the nonlocality of counterfactual quantum protocols, we devise a distributed controlled NOT (DNOT) operation to transfer information in both directions at the same time. This new form of full-duplex communication, called quantum duplex coding, enables communicating parties to exchange either classical or quantum messages simultaneously and counterfactually by means of nonlocal controlled entanglement and/or disentanglement of the DNOT operation. We demonstrate the quantum duplex coding for both classical and quantum information using the (chained) quantum Zeno effect and show that these quantum duplex communication protocols form full-duplex binary and quantum erasure channels, respectively.